#!/usr/bin/env node

const log = console.log,
      pi = Math.PI;

function Circle(r){
  var _r = r;

  this.diameter = () => 2*_r;
  this.circumference = () => pi*2*_r;
  this.area = () => pi*_r*_r;
}

try{
  module.exports = Circle;

  log(module);
}catch(e){
    console.error('something wrong!');
  }

